the answer is -$97 for sure.
! O% W( Z6 x& k4 _- l& wThink about it this way TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。# \( L1 `. b$ q! T! g# J. U
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18); \5 u$ l! G9 c. T, L: P7 B% ?
2) Now, the owner discovered that the 100 bucks is fake. You can think this as a lost of $100. therefore the overall gain is $3-$100 = -$97 |